Merge pull request yt-project#114 from saethlin/master

Fix unit hash function
ngoldbaum · Dec 30, 2019 · a2645f8 · a2645f8
2 parents e7b198d + 6d81f73
commit a2645f8
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diff --git a/unyt/tests/test_units.py b/unyt/tests/test_units.py
@@ -791,3 +791,14 @@ def test_percent():
 
     assert a == c
     assert c == d
+
+
+def test_equal_has_same_hash():
+    a = Unit("m")
+    b = Unit("m")
+    c = Unit("m*s/s")
+
+    assert a == b
+    assert b == c
+    assert hash(a) == hash(b)
+    assert hash(b) == hash(c)
diff --git a/unyt/unit_object.py b/unyt/unit_object.py
@@ -317,7 +317,7 @@ def units(self):
         return self
 
     def __hash__(self):
-        return super(Unit, self).__hash__()
+        return hash(self.registry.unit_system_id) ^ hash(self.expr)
 
     # end sympy conventions